e65c331b8f
This commit adds pgstat_prep_pending_from_entry_ref(), a new pgstats routine that is able to prepare an existing PgStat_EntryRef to receive pending stats. This split gives a way for callers to obtain first a reference via pgstat_get_entry_ref(), then set up pending data as two separate, distinctive, steps. Previously, the only way to get an entry reference with pending data ready was pgstat_prep_pending_entry(), which bundles lookup, creation, and pending setup in a single call. Callers that need finer control over the entry creation had no way to attach pending data to an already-obtained entry reference. One case where this has shown to matter for a stats kind is where one wants to check some capacity (for example where a GUC bounds the maximum numer of entries allowed) before deciding if a new entry should be created. So this split can help in reducing calls to pgstat_get_entry_ref(), meaning less shmem hash table lookups. The only logical ordering change is that pgStatPendingContext is initialized after calling pgstat_get_entry_ref() in pgstat_prep_pending_entry(). This does not matter in practice. pgstat_prep_pending_entry() is refactored to use the new function internally. All the existing callers are unchanged. Existing out-of-core custom stats kinds should see no impact. Author: Sami Imseih <samimseih@gmail.com> Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com> Reviewed-by: Michael Paquier <michael@paquier.xyz> Discussion: https://postgr.es/m/CAA5RZ0sV+TsLejUMhAM=PJoOm8u-t8ru7B67KvyLCy=19sM87g@mail.gmail.com
PostgreSQL Database Management System
This directory contains the source code distribution of the PostgreSQL database management system.
PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings.
Copyright and license information can be found in the file COPYRIGHT.
General documentation about this version of PostgreSQL can be found at https://www.postgresql.org/docs/devel/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/devel/installation.html.
The latest version of this software, and related software, may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.